www.aleph1.co.uk Git - yaffs-website/blob - node_modules/esprima/README.md

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   5
   6 **Esprima** ([esprima.org](http://esprima.org), BSD license) is a high performance,
   7 standard-compliant [ECMAScript](http://www.ecma-international.org/publications/standards/Ecma-262.htm)
   8 parser written in ECMAScript (also popularly known as
   9 [JavaScript](https://en.wikipedia.org/wiki/JavaScript)).
  10 Esprima is created and maintained by [Ariya Hidayat](https://twitter.com/ariyahidayat),
  11 with the help of [many contributors](https://github.com/jquery/esprima/contributors).
  12
  13 ### Features
  14
  15 - Full support for ECMAScript 2016 ([ECMA-262 7th Edition](http://www.ecma-international.org/publications/standards/Ecma-262.htm))
  16 - Sensible [syntax tree format](https://github.com/estree/estree/blob/master/es5.md) as standardized by [ESTree project](https://github.com/estree/estree)
  17 - Experimental support for [JSX](https://facebook.github.io/jsx/), a syntax extension for [React](https://facebook.github.io/react/)
  18 - Optional tracking of syntax node location (index-based and line-column)
  19 - [Heavily tested](http://esprima.org/test/ci.html) (~1300 [unit tests](https://github.com/jquery/esprima/tree/master/test/fixtures) with [full code coverage](https://codecov.io/github/jquery/esprima))
  20
  21 ### API
  22
  23 Esprima can be used to perform [lexical analysis](https://en.wikipedia.org/wiki/Lexical_analysis) (tokenization) or [syntactic analysis](https://en.wikipedia.org/wiki/Parsing) (parsing) of a JavaScript program.
  24
  25 A simple example on Node.js REPL:
  26
  27 ```javascript
  28 > var esprima = require('esprima');
  29 > var program = 'const answer = 42';
  30
  31 > esprima.tokenize(program);
  32 [ { type: 'Keyword', value: 'const' },
  33   { type: 'Identifier', value: 'answer' },
  34   { type: 'Punctuator', value: '=' },
  35   { type: 'Numeric', value: '42' } ]
  36
  37 > esprima.parse(program);
  38 { type: 'Program',
  39   body:
  40    [ { type: 'VariableDeclaration',
  41        declarations: [Object],
  42        kind: 'const' } ],
  43   sourceType: 'script' }
  44 ```